In a sensational turn of events, West Bengal Chief Minister Mamata Banerjee on Thursday accused the Central government of "deploying the army" along highway toll plazas while keeping the state government "in the dark" and vowed to stay put at the secretariat till the soldiers are withdrawn from a toll gate close to it.

"I won't leave unless the army is withdrawn from near the secretariat. I'll be there as a guard to protect democracy, to protect my democratically elected government," Banerjee told a hurriedly convened late night media meet at the secretariat Nabanna in Howrah district.

The said toll plaza at the foot of the Vidyasagar Setu, also called the second Hooghly Bridge, is about 500 m from the secretariat.

In high drama that unfolded late Thursday , the Defence Ministry denied the charge and said the army was conducting a routine exercise with full co-ordination with the West Bengal police.

"The army conducts the annual exercise throughout the county with the aim of getting statistical data about the load carriers that could be made available to the army in case of a contingency," said a Defence ministry spokesman.

Rubbishing the spokesman's clarification, Banerjee said it was a lie. "The National Highway Authority of India has all this data. They have records of the number of cars plying in each state, and through each highway."

She also tweeted: "Absolutely wrong and misleading facts by @easterncomd. We have great respect for you, but please please don't mislead the people."

A little after midnight, the Eastern Command said the army has been asked to withdraw from the toll plaza near Nabanna.

"As far as the toll plaza at Nabanna is concerned, it may be understood that the requisite data had been gathered and therefore the army has been asked to withdraw from that specific point. They would be deployed elsewhere tomorrow," the Command said.

Banerjee, also supremo of the ruling Trinamool Congress, said she has collected information from Maharashta, Kerala, Odisha and Chhattisgarh.

"This is not being done anywhere. Why is it been done in Bengal? Is it because I am speaking for the people," she asked.

"They can ask the army to shoot me, I may live or die. But I will fight to give protection to my democratic government," she said, claiming the army has been positioned in Jalpaiguri, Alipurduar, Darjeeling, North 24Parganas, Howrah, Hooghly, Kolkata, Murshidabad and Burdwan districts.

Banerjee said: "The secretariat "Nabanna" is a sensitive zone. The toll plaza on the second Hooghly Bridge is within the sensitive zone. It is under our secretariat."

Demanding to know whether a military coup has taken place, she said "the motive is political, vindictive, unconstitutional, unethical and undemocratic".

"I don't know what they may do at night.

So for the people's sake I will stay put here at night," she said.

Besides the chief minister, a number of ministers and the Home Secretary, State Director General of Police, the Kolkata Police Commissioner were all present at the secretariat past midnight.

Banerjee said despite the city police commissioner informing the army about the state government's objection to their presence, the army men refused to budge.

Banerjee alleged that the army was taking money from the people at the toll plazas, and called it "loot".

Earlier, in the evening Banerjee said the Chief Secretary was writing to the central government and she would approach President Pranab Mukherjee to seek clarification over the alleged deployment of the army at the Dankuni and Palsit toll plazas on National Highway 2 (connecting Delhi and Kolkata).

"Army has been deployed in the state without informing the state government. This is unacceptable. Federal structure has been disrupted and democracy twisted. Has Emergency been declared?" she asserted.

"Even if the Army carried out a mock exercise, the state government should have been kept in the loop. If this is happening in a civil area in Bengal, this could happen in Bihar, next in Uttar Pradesh, then in Tamil Nadu and other states as well. It is a very serious situation and it is dangerous than Emergency. We are facing an extremely black day," she said.

"I'll urge all state governments to look into the matter. A team of Opposition... all political leaders... will meet the president (soon)," she added.

Soon after Banerjee's allegations, the spokesman said there was "nothing alarming about this" and the exercise is carried out as per government orders.

"The army is carrying out it's routine exercise in all states of the eastern region including West Bengal. Permission for carrying out this exercise in West Bengal was initially sought for November 28 on specific request of the police the date had been shifted to December 1. No permission has been withdrawn so far," the spokesman added.